This invention relates to shims for machinery, more specifically to a slotted shim for spacing apart a machine base and a support for the machine, and adapted to receive in its slot machine-securing bolt means extending between the base and the support.
In installing or maintaining machinery such, for example, as motors, pumps, turbines, compressors, die stampers, punch presses, gear boxes and journal boxes, it often is necessary precisely to align or level one machine with respect to another machine or equipment which is coupled thereto or otherwise cooperates therewith, or to align different components of the same machine with respect to each other, for proper operation. Thus, for example, when a motor directly drives a pump, efficient performance of the combination is aided by having the shafts of the motor and pump in axial alignment.
Machines commonly are mounted on supports therefor by releasably securing the bases of the machines to the supports by bolt means, including bolts, studs, and other rod-like connectors, having elongate shanks or the like which extend between the bases and their supports. Approximate alignment or leveling of a machine is accomplished by appropriate positioning or placement of its support. Precise alignment then is attained by inserting one or more shims between the machine base and its support, to adjust the spacing therebetween.
In order to preserve an alignment obtained by shimming and to minimize unwanted movement, it is desirable that a shim or shims support or cover a maximum proportion of the supported surface or surfaces of the machine base. When a bolt means extends through such a surface to connect the machine to its support, maximum shim support is provided by inserting a plurality of shims around the bolt means, or by inserting a shim or shims having a bolt means-receiving slot or hole therein. Slotted shims are preferred for insertion between a machine base and a support without need to remove one from the other, while minimizing the number of shims and attendant labor.
Shims may be custom-made, as needed for a job, by hand-cutting pieces from commercially available shim stock of predetermined thickness. However, hand-cutting can result in the formation of burrs that are hazardous to the user. Hand-cut shims may be relatively expensive, particularly, when they are made on the job by high-priced labor performing machine-setup work. Also, there is wastage of the shim stock.
Shims which are pre-cut in standard shim and slot sizes are available commercially. While they obviate the foregoing disadvantages of custom-made shims, the pre-cut shims, as well as the custom-made shims, may be damaged in use, particularly during insertion between the machine base and its support.
Shimming a machine to effect the final adjustment of its position relative to its support often is carried out with the machine set on its support and its securing bolt means in place, but not tightened. Frequently, the medial portion of the bolt means, between the base of the machine and the support, is hidden from view by machine and support structure. Consequently, when a slotted shim is inserted between the base and the support at a bolt means location, it may be necessary to feel about blindly with the front end of the shim, to align the shim slot with the bolt means. During such an insertion, the shim, particularly one having a thin gauge, may be bent by snagging its front end on the bolt means, so that it must be discarded. The time required to insert the shim properly also may increase, with a resultant increase in labor cost.